The present invention relates to a voice input-output device and a communication device.
It is desirable to pick up only desired sound (user's voice) during a telephone call, speech recognition, voice recording, or the like. However, sound (e.g., background noise) other than desired sound may also be present in an environment in which a voice input device is used. Therefore, a voice input device has been developed which has a function of removing noise.
As technology which removes noise in an environment in which noise is present, a method which provides a microphone with sharp directivity, and a method which detects the travel direction of sound waves utilizing the difference in time when sound waves reach a microphone and removes noise by signal processing have been known.
In recent years, electronic instruments have been increasingly scaled down. Therefore, technology which reduces the size of a voice input device has become important (see JP-A-7-312638, JP-A-9-331377, and JP-A-2001-186241).
In order to provide a microphone with sharp directivity, it is necessary to arrange a number of diaphragms. This makes it difficult to reduce the size of a voice input device.
In order to detect the travel direction of sound waves utilizing the difference in time when sound waves reach a microphone unit, a plurality of diaphragms must be provided at intervals equal to a fraction of several wavelengths of an audible sound wave. This also makes it difficult to reduce the size of a voice input device.
When using a voice input-output device (e.g., telephone, portable telephone, or headset microphone-speaker unit) in a noise-containing environment, it is generally difficult to clearly catch a voice through the voice input-output device.